var persisteduls=new Object();
var ddtreemenu=new Object();

ddtreemenu.closefolder="images/arrowrightGreen.png"; //set image path to "closed" folder image
ddtreemenu.openfolder="images/arrowdownGreen.png"; //set image path to "open" folder image

//////////No need to edit beyond here///////////////////////////

ddtreemenu.createTree=function(treeid, enablepersist, persistdays){
	var ultags=document.getElementById(treeid).getElementsByTagName("ul");
	if (typeof persisteduls[treeid]=="undefined")
		persisteduls[treeid]=(enablepersist==true && ddtreemenu.getCookie(treeid)!="")? ddtreemenu.getCookie(treeid).split(",") : "";
	for (var i=0; i<ultags.length; i++)
		ddtreemenu.buildSubTree(treeid, ultags[i], i);
	if (enablepersist==true){ //if enable persist feature
		var durationdays=(typeof persistdays=="undefined")? 1 : parseInt(persistdays);
		ddtreemenu.dotask(window, function(){ddtreemenu.rememberstate(treeid, durationdays)}, "unload"); //save opened UL indexes on body unload
	};
};

ddtreemenu.buildSubTree=function(treeid, ulelement, index){
	ulelement.parentNode.className="submenu";
	if (typeof persisteduls[treeid]=="object"){ //if cookie exists (persisteduls[treeid] is an array versus "" string)
		if (ddtreemenu.searcharray(persisteduls[treeid], index)){
			ulelement.setAttribute("rel", "open");
			ulelement.style.display="block";
			ulelement.parentNode.style.backgroundImage="url("+ddtreemenu.openfolder+")";
		}
		else
			ulelement.setAttribute("rel", "closed");
	} //end cookie persist code
	else if (ulelement.getAttribute("rel")==null || ulelement.getAttribute("rel")==false) //if no cookie and UL has NO rel attribute explicted added by user
		ulelement.setAttribute("rel", "closed");
	else if (ulelement.getAttribute("rel")=="open") //else if no cookie and this UL has an explicit rel value of "open"
		ddtreemenu.expandSubTree(treeid, ulelement); //expand this UL plus all parent ULs (so the most inner UL is revealed!)
		ulelement.parentNode.onclick=function(e){
		var submenu=this.getElementsByTagName("ul")[0];
		if (submenu.getAttribute("rel")=="closed"){
			submenu.style.display="block";
			submenu.setAttribute("rel", "open");
			ulelement.parentNode.style.backgroundImage="url("+ddtreemenu.openfolder+")";
		}
		else if (submenu.getAttribute("rel")=="open"){
			submenu.style.display="none";
			submenu.setAttribute("rel", "closed");
			ulelement.parentNode.style.backgroundImage="url("+ddtreemenu.closefolder+")";
		}
		ddtreemenu.preventpropagate(e);
	};
	ulelement.onclick=function(e){
		ddtreemenu.preventpropagate(e);
	};
};

ddtreemenu.expandSubTree=function(treeid, ulelement){ //expand a UL element and any of its parent ULs
	var rootnode=document.getElementById(treeid);
	var currentnode=ulelement;
	currentnode.style.display="block";
	currentnode.parentNode.style.backgroundImage="url("+ddtreemenu.openfolder+")";
	while (currentnode!=rootnode){
		if (currentnode.tagName=="UL"){ //if parent node is a UL, expand it too
			currentnode.style.display="block";
			currentnode.setAttribute("rel", "open"); //indicate it's open
			currentnode.parentNode.style.backgroundImage="url("+ddtreemenu.openfolder+")";
		}
		currentnode=currentnode.parentNode
	}
}

ddtreemenu.flatten=function(treeid, action){ //expand or contract all UL elements
	var ultags=document.getElementById(treeid).getElementsByTagName("ul");
	for (var i=0; i<ultags.length; i++){
		ultags[i].style.display=(action=="expand")? "block" : "none";
		var relvalue=(action=="expand")? "open" : "closed";
		ultags[i].setAttribute("rel", relvalue);
		ultags[i].parentNode.style.backgroundImage=(action=="expand")? "url("+ddtreemenu.openfolder+")" : "url("+ddtreemenu.closefolder+")";
	}
};

ddtreemenu.rememberstate=function(treeid, durationdays){ //store index of opened ULs relative to other ULs in Tree into cookie
	var ultags=document.getElementById(treeid).getElementsByTagName("ul");
	var openuls=new Array();
	for (var i=0; i<ultags.length; i++){
		if (ultags[i].getAttribute("rel")=="open")
			openuls[openuls.length]=i; //save the index of the opened UL (relative to the entire list of ULs) as an array element
	}
	if (openuls.length==0) //if there are no opened ULs to save/persist
		openuls[0]="none open"; //set array value to string to simply indicate all ULs should persist with state being closed
	ddtreemenu.setCookie(treeid, openuls.join(","), durationdays); //populate cookie with value treeid=1,2,3 etc (where 1,2... are the indexes of the opened ULs)
};

////A few utility functions below//////////////////////

ddtreemenu.getCookie=function(Name){ //get cookie value
	var re=new RegExp(Name+"=[^;]+", "i"); //construct RE to search for target name/value pair
	if (document.cookie.match(re)) //if cookie found
		return document.cookie.match(re)[0].split("=")[1]; //return its value
	return "";
}

ddtreemenu.setCookie=function(name, value, days){ //set cookei value
	var expireDate = new Date();
	//set "expstring" to either future or past date, to set or delete cookie, respectively
	var expstring=expireDate.setDate(expireDate.getDate()+parseInt(days));
	document.cookie = name+"="+value+"; expires="+expireDate.toGMTString()+"; path=/";
}

ddtreemenu.searcharray=function(thearray, value){ //searches an array for the entered value. If found, delete value from array
	var isfound=false
	for (var i=0; i<thearray.length; i++){
		if (thearray[i]==value){
			isfound=true;
			thearray.shift();//delete this element from array for efficiency sake
			break;
		}
	}	
	return isfound;
}

ddtreemenu.preventpropagate=function(e){ //prevent action from bubbling upwards
	if (typeof e!="undefined")
		e.stopPropagation();
	else
		event.cancelBubble=true;
}

ddtreemenu.dotask=function(target, functionref, tasktype){ //assign a function to execute to an event handler (ie: onunload)
	var tasktype=(window.addEventListener)? tasktype : "on"+tasktype;
	if (target.addEventListener)
		target.addEventListener(tasktype, functionref, false);
	else if (target.attachEvent)
		target.attachEvent(tasktype, functionref);
}